Method of making metallic-lined pressure vessel



April 4, 1967 G. T. CORBIN, JR 3,312,5'25

I METHOD OF MAKING METALLIC-LINED-PRESSURE VESSEL Original Filed Sept.11, 1963 FIG. I.

INVENTOR. GEORGE T. CORBIN, JR

BY W ,ww

ATTYS.

United States Patent Ofiice 3 ,3 12,5 75 Patented Apr. 4, 1967 3,312,575METHOD OF MAKING METALLIC-LINED PRESSURE VESSEL George T. Corbin, Jr.,421 Byberry Road,

Huntingdon Valle Pa. 19006 Continuation of abandoned application Ser.No. 308,143, Sept. 11, 1963. This application Mar. 7, 1966, Ser. No.532,476

4 Claims. (Cl. 156-151) This invention relates to a fluid-retainingpressure vessel and method of making it and has for an object theprovision of improvements in this art.

This application is a continuation of parent application Ser. No.308,143, filed Sept. 11, 1963, now abandoned.

In a copending application, Ser. No. 227,330, filed Oct. 1, 1962, nowPatent No. 3,214,506, there is disclosed a method and apparatus forcasting a disposable mandrel to be used for forming a strong vessel bywinding thereon a covering of strand material such as fiber glass unitedby a strong rigidifying plastic, such as an epoxy or the like, andsubsequently removing the mandrel by dissolving it and washing it outwith a liquid, such as water. The vessel produced is very strong butcannot be depended upon to retain fluids, such as gases under highpressure. It is usual to provide vessels with very thick heavy metalwalls for containing gases under high pressure and they can regularly beseen in use for transporting oxygen, carbon-dioxide, hydrogen, helium,methane, propane and the like.

A vessel made of fiber glass and plastic isextremely strong for itsweight. Compared to a steel container for the same pressure capacity afiber glass and plastic container would weigh only one-third or less andsince the weight of the contained gas is relatively negligible, it willbe seen that if a fiber glass container could be made to resist gasleakage with certainty it would provide the very high strength and lowweight which are so desirable. Such vessels could easily be lifted andhandled by one man and eliminate the use of hoists, derricks, additionalmen and the like now required.

The present invention provides such a desirable lightweightfluid-impervious vessel by disposing a thin metal liner within thestrong light weight outer body of the vessel. Such a metal liner can bevery thin since it need only provide the desired fluid-tightness, theouter body providing the strength and rigidity needed.

It would be impractical for many reasons to try to coat the inside of aformed container with a very thin layer of metal. First, the space isinaccessible; next, there can be no dependable inspection or certaintyof the coating being fluid-impervious; and, further, it would be almostimpossible to secure a smooth inner surface and uniform thickness ofcoating, both very desirable to resist the beginning of rupture.

It would also be impractical to try to make a thin metal vessel and thenwind the outer vessel body on it. First, it would be impossible to makean independent vessel with such a thin uniform wall; next, such a vesselwould not be self-sustaining for handling; and, further, it would becrushed by the winding operation for forming the body of the vessel.

According to the present invention the desired line fluid-imperviouslight-weight high-strength vessel is produced by forming a strong,smooth, rigid wash-out type mandrel, forming a thin jacket offluid-imperviou material thereon, forming a strong light vessel bodyover and adherent to the fluid-impervious jacket while supported on therigid mandrel, and then washing out the mandrel after the lined vesselbody has been completed.

The objects, novel features and advantages of the invention will beapparent from the following description of an exemplary embodimentthereof, reference being made to the accompanying drawings, wherein:

FIG. 1 is a sectional view of a mandrel having formed thereon a fluidimpervious jacket;

FIG. 2 is a sectional view of the mandrel and jacket with the stronglight vessel body formed thereon;

FIG. 3 is a sectional view of the finished vessel after the mandrel hasbeen dissolved in and flushed out by a liquid.

In FIG. 1 there is shown a hollow mandrel 10 made of a hard, liquidsoluble plastic material, such as Paraplast marketed by Rezolin Inc. ofSanta Monica, California, according to the method and apparatus referredto in the above-mentioned copending application. The mandrel is formedwith holes 11 at opposite ends or in at least one end.

Over the mandrel 10 there is formed a thin fluid impervious coaiting orjacket 12. In one embodiment this coating may be a metal such as ductilenickel and may be applied upon the mandrel, as by electro-forming orelectro-plating. It will serve its purpose if no more than .030" thick.

At the ends of the mandrel there are secured, as by brazing to the metaljacket, base-flanged pole pieces 13 which aid in further operations andserve to hold gas retaining plugs in the finished vessel. The termbrazing includes soldering. The pole pieces are provided with holeswhich align with the holes in the mandrel and the holes in the polepieces are threaded for receiving supporting shaft elements or closureplugs.

As shown in FIG. 2, a vessel body 14 is formed over the jacket 12 whileit is still supported on, the mandrel. The body 14 may be formed offiber glass strands tightly cross wound and impregnated with a stronghardening adhesive, such as an epoxy, in known manner.

After the vessel body 14 has been formed and hardened, the mandrel isremoved by dissolving it with liquid and washing it out. The presentlypreferred mandrel material, mentioned above, is soluble in water. Careis taken during operations to avoid moisture in the air which woulddamage the mandrel so the plant is one having a controlled atmosphere,low in moisture content.

A vessel body /8" thick provides as much strength against bursting atthe pressures used as common portable steel tanks; and since thematerial does not stretch appreciably at the pressures used, there is nodanger of rupturing the thin layer 12 which now forms a gas imperviousliner within the strong container body. The pole pieces have baseflanges over which the body is wound.

The light, strong, gas-impervious vessel thus formed is very desirable,especially for use in aircraft where weight is such an undesirablefactor.

While one embodiment of the invention has been described for purposes ofillustration, it is to be understood that there may be variousembodiments and modifications within the general scope of the invention.

I claim:

1. The method of making a light-weight high-pressure fluid-storagevessel, which comprises electroforming on a rigid, smooth, fluid-solublemandrel a substantially uniform fluid-impervious jacket of ductilenickel, forming over said jacket a high-strength, light-weight vesselbody of wound strands impregnated with a strong hardening adhesive whilesaid jacket is on said mandrel, and then dissolving said mandrel toseparate it from said jacket and to leave said jacket as a liner in saidvessel body, said liner :being electroformed to a thickness less thanthat required to prevent bursting thereof if filled with fluid at highpressure in the absence of said vessel body and said vessel body havinga thickness sufiicient to prevent bursting when said liner is filledwith said fluid at high pressure.

2. The method of claim 1 in which said mandrel is water soluble and saiddissolving comprises exposing said mandrel to water.

3. The method of claim 1, comprising the step of brazing on said jacket,prior to forming of said vessel body, at least one pole piece having aflanged base disposed against the outside of said jacket and having anaperture therethrough communicating with the interior of said jacket,said vessel body being formed over the flange of said base.

4. The method of making a light-weight high-pressure fluid-storagevessel, whichcomprises electroforming on a rigid, smooth, fluid-solublemandrel a substantially uniform fluid-impervious jacket of ductilenickel less than about 0.030 inch in thickness, forming over said jacketa high-strength light-weight vessel body of wound fiber glass strandsimpregnated with a strong hardening adhe' sive to provide a vesselthickness a number of times greater than said jacket thickness whilesaid jacket is on said mandrel, and then dissolving said mandrel toseparate it from said jacket and to leave said jacket as a liner in saidvessel body, whereby said vessel body provides strength to resistbursting due to the high pressures of fluid stored in said vessel andsaid liner prevents leakage of said fluid through the walls of saidvessel.

References Cited by the Examiner UNITED STATES PATENTS 2,826,524 3/1958Molloy 156155 X 3,137,405 6/1964 Gorcey 2203 FOREIGN PATENTS 747,7774/1956 Great Britain.

OTHER REFERENCES IBM, Technical Disclosure Bulletin, ElectrodepositedThin Metallic Film Elements, J. C; Lloyd et al., col. 3, No. 93,February 1961.

EARL M. BERGERT, Primary Examiner.

PHILIP DIER, Examiner.

1. THE METHOD OF MAKING A LIGHT-WEIGHT HIGH-PRESSURE FLUID-STORAGEVESSEL, WHICH COMPRISES ELECTROFORMING ON A RIGID, SMOOTH, FLUID-SOLUBLEMANDREL A SUBSTANTIALLY UNIFORM FLUID-IMPERVIOUS JACKET OF DUCTILENICKEL, FORMING OVER SAID JACKET A HIGH-STRENGTH, LIGHT-WEIGHT VESSELBODY OF WOUND STRANDS IMPREGNATED WITH A STRONG HARDENING ADHESIVE WHILESAID JACKET IS ON SAID MANDREL, AND THEN DISSOLVING SAID MANDREL TOSEPARATE IT FROM SAID JACKET AND TO LEAVE SAID JACKET AS A LINER IN SAIDVESSEL BODY, SAID LINER BEING ELECTROFORMED TO A THICKNESS LESS THANTHAT REQUIRED TO PREVENT BURSTING THEREOF IF FILLED WITH FLUID AT HIGHPRESSURE IN THE ABSENCE OF SAID VESSEL BODY AND SAID VESSEL BODY HAVINGA THICKNESS SUFFICIENT TO PREVENT BURSTING WHEN SAID LINER IS FILLEDWITH SAID FLUID AT HIGH PRESSURE.